An External Load Bearing Distracting Device For An Articulating Anatomical Joint

ABSTRACT

An external load bearing distracting device for unloading a human knee joint cartilage while providing the knee joint normal motion. The device has a first component attached to a first anatomical member of an articulating anatomical joint and a second component operably associated with the first component; a third component attached to a second member of the anatomical joint and a fourth component operably associated with the third component; and a joint joining the second component and the fourth component. The first component is slidably arranged inside the second component, and the third component is slidably arranged inside the fourth component. The second and the fourth component each include a retaining component for limiting movement along a longitudinal axis of the components.

BACKGROUND OF THE INVENTION Field of the Invention

The present invention relates to an external load bearing distractingdevice for an articulating anatomical joint. In a preferred embodiment,the articulating anatomical joint is a knee joint. More particularly,the present invention relates to the external load bearing distractingdevice which can be positioned to unload a knee joint while providingits normal motion and can be adjusted to distract and fully unload theknee joint cartilage. The present invention is intended for useparticularly, but not exclusively, to treat osteoarthritis (OA), focalcartilage defects and treatment of fractures occurred inside the kneejoint.

Brief Description of the Prior Art

The knee joint is subject to many types of traumatic injuries andpathological conditions which result in soft tissue rupture,dislocation, bone fracture, cartilage erosion, or infection. The currentmethods of treatment are usually rest, bracing, casting, internalfixation, external fixation, ligamentous reconstruction, prostheticreplacement or a combination of the above.

Immobilization has been found to be less than satisfactory because itcan reduce subsequent motion of the joint, sometimes permanently. Softtissue repairs are adversely affected by both immobilization andmobilization, unless the latter is prevented from overstretching thetissues before healing occurs.

External linkages would not suffer from the above shortcomings but havebeen unsatisfactory in the past because they provide only approximatemotion and are not compatible with the more exacting motion requirementsof the internal structures of the knee joint. A device which allowsphysiological motions of the knee and which in parallel providesunloading of the knee joint would thus be of a great clinical benefitand would enable further advances in the knee joint treatment.

It has been known that the joint surfaces of the knee undergo acombination of rolling and sliding, that the medial and lateral sidesmove differently and that there is a transverse rotation of the femurabout the longitudinal axis of the tibia, especially towards theextension position. This is known as the “screw-home” mechanism.Actually, the movements of the knee joint include six degrees of freedomof motion namely 3 translations (antero-posterior, media-lateral anddistraction-compression) and 3 rotations (flexion-extension,varus-valgus and internal-external).

The physiological motion of the human knee involves an extremely complex“polycentric” motion wherein the center of rotation of the tibia withrespect to the femur varies as a function of the angle of rotation. Thismotion is caused by simultaneous movements of the interacting surfacesinvolved in articulation of the knee, including: internal-externalrotation of the tibia relative to the femur about a vertical axis;movement between the femoral and tibial parts about a horizontal,anterior-posterior axis; and sliding and anterior-posterior rolling ofends of the femoral and tibial parts in an anterior-posterior plane. Thephysiological motion of the tibia relative to the femur is furthercomplicated by the three-dimensional component of motion outside thesagittal plane, and by the contribution of ligaments, tendons andcartilage structure.

The above can be best understood with reference to FIGS. 1 and 2 whichare a schematic representation of the knee joint as seen from the medialor lateral side, and in a perspective view. As seen there, the tibiaincludes upper joint load-bearing surfaces A which are slightly curvedand slope downward in a posterior direction relative to the longitudinalaxis of the tibia. The femur includes lateral and medial condyles whoseload-bearing surface outlines B can be approximated by circular arcs.That is, the centers of curvature C of those portions of theload-bearing surface which are in contact with the tibia at variousangles of flexure are not identical. As seen in FIG. 1, at small degreesof flexion the arc which is defined by the load-bearing surface has aninstantaneous center of curvature C. However, at greater flexion of theknee the arc defined by the load-bearing surface has an instantaneouscenter of curvature C′ which is different from the previously mentionedarc. Instantaneous centers of curvature C to C′, through which centersan axis of rotation of the knee joint undergoes, indicates aninstantaneous center of curvature only for the specified arc of motion.The path of the serial locations of the instantaneous centers ofcurvature during flexion-extension of the knee joint is called theevolute. All movements of the centers of rotation differ from knee toknee and from the medial to the lateral sides of a given knee. In manypractical clinical situations, it is necessary to make simple estimatesof the location of the axis of rotation of the knee joint. A series ofradiographs is required to precisely identify the instantaneous axis ofrotation at a knee joint. This method is not practical in ordinaryclinical situations. However, according to recent developments in thearea of knee kinematics it has been discovered that “one” axis occursthroughout the most arc of motion. The review of the development ofconcepts of knee kinematics is disclosed in publication “Development ofthe concepts of knee kinematics” by Smith P N et al, published 2003December; 84(12): 1895-902, where the derivation of theflexion-extension axis by using 3-dimensional imaging technology wasapplied. According to said review, “one” posterior condylar axis iseffective from 15° to 150° of the knee flexion. This axis passes throughthe origins of the medial (MCL) and lateral collateral ligaments (LCL)and passes through the intersection of the cruciate ligaments. Itclosely approximates the epicondylar line and is offset from thesagittal plane by 7°. Further, in said publication the description ofthe screw-home mechanism can be overcome by external forces duringactive movement. Additionally, cited authors Blankevoort et al and LaFortune et all found no evidence of screw-home mechanism in vivo. Inconclusion of the said publication, the model of the knee as aball-and-socket joint is a model in which the knee can function.Further, it is recommended to the designers of knee prosthesis not toapply a roll back design but rather to incorporate freedom or control oflongitudinal rotation, which recommendation has been incorporated in thepresent invention, particularly freedom of longitudinal rotation.

The concept of rolling one surface on another was utilized in thestructure disclosed in “Restoration of Function in the Knee and Elbowwith a Hinge Distractor Apparatus” by Volkov et al (see The Journal OfBone and Joint Surgery, Vol. 57-A, No. 5, July 1975, pp. 591 to 600). Inthe design there described, two transverse pins through the femur andtibia held an adjustable rack and pinion on the medial and lateral sidesas well as a locking mechanism anteriorly. Traction bows encircled theanterior halves of the shank and thigh. The rack and pinion arrangementutilized the concept of rolling one surface on another. However, thisdesign was complex and did not accurately approximate the motion of theknee. The rack and pinion resulted in backward motion of the femoralcondyles on the tibial condyles during flexion. Moreover, there were nodifferences in motion between the medial and lateral sides of the joint.

The prior art document published under no. WO2011049796 on 28 Apr. 2011is directed to the implantable assemblies for manipulating energytransferred by means of flexing absorbing members, wherein said meansare configured to flex and absorb energy transferred by the members ofthe anatomical joint. Document no. US2004260302 published on 23 Dec.2004 discloses an internal brace for distraction arthroplasty, theinternal brace includes femoral and tibial components which can be fixedto the patient's femur and tibia and which in combination distract orseparate the knee joint without substantially hindering mobility of theknee. The invention provides an implantable brace for use in a kneejoint, the implantable brace functions as a wedge in this meniscal spaceto distract or to open the joint where there has been unicompartmentarticulate cartilage narrowing, while enabling motion of the knee bothin anterior and posterior rolling motions and providing for rotationaland sagittal plane motion.

None of the prior art documents is directed to a device intended fortemporary distracting the knee joint and at the same time to allowmobility of the anatomical joint.

It is an object of the present invention to provide an externalload-bearing distracting device for the knee joint which distracts theknee joint and unloads the knee cartilage while positively enablingnatural motion of the knee and bearing a required portion of the load.

Another object of the present invention is to provide an externalload-bearing distracting device for the knee joint which providesflexion-extension of the knee joint in the range at least between 0-90°,wherein natural range of motion of the knee joint is not affected,particularly freedom of longitudinal rotation.

Another object of present invention is to provide an externalload-bearing distracting device for the knee joint which is temporallyattached to the patient, preferably for a period of 6 to 8 weeks, saiddevice is intended for use particularly, but not exclusively, inrelation to treatment of osteoarthritis (OA), focal cartilage defectsand treatment of fractures occurred inside the knee joint, wherein areduction of subsequent motion of the joint, after removal thedistracting device, is prevented.

SUMMARY OF THE INVENTION

The present invention provides an external load bearing distractingdevice for an articulating anatomical joint. The external load bearingdistracting device comprising a first component configured to beattached to a first anatomical member of an articulating anatomicaljoint, a second component operably associated with the first component;a third component configured to be attached to a second member of thearticulating anatomical joint, a fourth component operably associatedwith the third component; a retaining components; a means for adjustingand fixing the first component and the third component at desiredlongitudinal position in relation to a flexion-extension axis ofrotation of the articulating anatomical joint; and a joint joining thesecond and the fourth component, wherein the joint is configured toenable six degrees of motion of the articulating anatomical joint. Eachof said four components is carried out of one solid part, the firstcomponent and the second component are slidably and telescopicallyinterconnected and the third component and the fourth component areslidably and telescopically interconnected. The two of said fourcomponents, each of the two components is disposed on the mutuallyopposite side in relation to the mediolateral axis of the joint, eachcomprising one retaining component and the other two of said fourcomponents each comprising the means for adjusting and fixing the firstcomponent and the third component at desired longitudinal position inrelation to a flexion-extension axis of rotation of the articulatinganatomical joint, the means for adjusting and fixing the first componentand the third component at desired longitudinal position are positionedinside the respective retaining component. Each retaining component hasthe shape of a hollow frame. A segment of the first component isslidably and telescopically arranged inside the second component, and asegment of the third component is slidably and telescopically arrangedinside the fourth component, where all said components are capable ofrotating around a mediolateral axis, and the first and the thirdcomponent are capable of axially moving along the longitudinal axis;wherein the second and the fourth component each comprise the retainingcomponent operably associated with the means for adjusting and limitingaxial movement of the first and the third component inside the secondand the fourth component. Each central part of the first component andof the third component is provided with an external threaded portion,where on each external threaded portion are arranged the means foradjusting and fixing the first component and the third component atdesired longitudinal position, the means are one pair of nuts. Each pairof nuts is positioned inside the respective retaining component. Byvirtue of both pair of nuts and both retaining components, said firstand third component is each held at desired longitudinal positionproviding distraction of the articulating anatomical joint.

In another embodiment of the present invention, the first componentconfigured to be attached to the first anatomical member of anarticulating anatomical joint and the third component configured to beattached to the second member of the articulating anatomical joint areeach provided with the retaining component. Each retaining component isarranged on the proximal end of the first component and respectively onthe proximal end of the third component. In this embodiment of thepresent invention, a segment of the second component is slidably andtelescopically arranged inside the first component, and a segment of thefourth component is slidably and telescopically arranged inside thethird component, where all said components are capable of rotatingaround a mediolateral axis. The second component operably associatedwith the first component and the fourth component operably associatedwith the third component are both provided with the means for adjustingand fixing the first component and the third component at desiredlongitudinal position in relation to a flexion-extension axis ofrotation of the articulating anatomical joint. Each central part of thesecond component and of the fourth component is provided with anexternal threaded portion, where on each external threaded portion arearranged the means for adjusting and fixing the first component and thethird component at desired longitudinal position in relation to aflexion-extension axis of rotation of the articulating anatomical joint,the means are one pair of nuts. Each pair of nuts is positioned insidethe respective retaining component. By virtue of both pair of nuts andboth retaining components, said first and third component is each heldat desired longitudinal position providing distraction of thearticulating anatomical joint. Further, as well as described in firstvariant of the present invention, the joint is joining the second andthe fourth component, wherein the joint is configured to enable sixdegrees of motion of the articulating anatomical joint. Replacement ofposition and arrangement of the retaining components and of the meansfor adjusting and fixing the first component and the third component atdesired longitudinal position in relation to a flexion-extension axis ofrotation of the articulating anatomical joint presents another way ofcarrying out the invention and does not in any way affect thefunctionality of the invention.

In a preferred embodiment of the present invention the articulatinganatomical joint is a knee joint, where said first component is adaptedto be fixed to a femur of the knee joint and said third component isadapted to be fixed to a tibia of the knee joint.

In one embodiment of the present invention the joint joining the secondand the fourth component comprises a structure like a ball-and-ringjoint.

In another embodiment of the present invention the joint joining thesecond and the fourth component comprises a structure having mutuallyconnected a ball bearing and a cardan joint.

In both of the embodiments the joint enables natural movement of theknee joint, thus preventing a consequent shortening of the soft tissuestructures resulting in loss of motion of the knee joint after thedistracting device is removed.

Depending on the position of a degenerated articular cartilage surfaces,the external load bearing distracting device can be anchored at alateral or at a medial side of the articulating anatomical joint, orsimultaneously on both sides of the articulating anatomical joint.

BRIEF DESCRIPTION OF THE DRAWINGS

Various other objects, features and attendant advantages of the presentinvention will be more fully appreciated as the same become betterunderstood from the following detailed description when considered inconnection with the accompanying drawings in which like referencecharacters designate like or corresponding parts throughout the severalviews and wherein:

FIG. 1 is a schematic illustration, from the lateral or medial side, ofa knee joint;

FIG. 2 is a schematic illustration of a knee joint degrees of freedom ofmovement;

FIG. 3 is a schematic illustration from the side view of a distractingdevice according to one embodiment of the present invention;

FIG. 4 is front view of a distracting device from the FIG. 3;

FIG. 5 is a perspective view showing the distracting device anchored toa knee joint;

FIG. 6 is a cross section view from the front side of a joint accordingto one embodiment of the present invention;

FIG. 7 is a cross section view of the joint from FIG. 6 from the lateralside;

FIG. 8 is a schematic illustration from the front view of a jointaccording to another embodiment of the present invention; and

FIG. 9 is a cross section view of the joint from FIG. 8 from the frontside.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Although the knee joint is being described here, it is contemplated thatthese devices can also be placed at other articular, cartilaginousjoints throughout the body, and some non-articular, non-cartilaginousjoints that are capable of motion in a flexion/extension direction thatexceeds forty-five degrees. As best seen in FIG. 1, the tibia loadbearing surface A is simulated as a planar surface while the femoralcondylar load bearing surfaces are simulated as circular load bearingsurfaces B having centrodes moving from point 1 to point 4 during theflexion of the knee. That is, it has been determined that the rollingand sliding motion of the knee joint causes the centrode to move from 1to 4 during flexure, the distance 1-4 varying between the lateral andmedial compartments. According to the recent developments in in the areaof knee kinematics it has been detected as screw-home mechanism is basedon 2-dimensional passive models, and in addition authors Bankevoort etal and La Fortune et al found no evidence of screw-home mechanism invivo. Instead, “one” posterior condylar axis is effective from 15° to150° of knee flexion, hereafter referring to a flexion-extension axis ofthe knee joint. Thus, the present invention attempts to provide a devicewhich enables natural movement of the knee joint and distracts the kneejoint in a longitudinal direction (in a sagittal plane) to the distancecorresponding at least to a healthy knee joint. Distracting the kneejoint to distance corresponding at least to the healthy knee joint, fora period of time determined by the medical indications, enables recoveryof the cartilage defects related to various knee joint diseases orinjuries. In a knee distraction surgery, femur and tibia bones areslightly pulled apart and held into place by a plurality of pins whichprotrude from the skin in an external fixation, where a joint of anexternal load bearing distracting device enables natural movement of theknee joint. Patient wear the distraction device for 6 to 8 weeks toallow cartilage to regenerate. With the bone-on-bone alleviated thearticular cartilage can now repair itself without the weight andmechanical stress of the “bone on bone”. The knee distraction procedurecan be combined with other knee treatments such as applying treatmentwith hyaluronic acid or stem cells treatment for cartilage tissueregeneration, or injecting signaling molecules or any other local orsystemic treatment of the knee joint.

The present invention distracts the load bearing surfaces A and B byproviding an external load bearing distracting device mounted to thelateral or medial sides of a tibia and a femur, possibly bytranscutaneous transverse pins.

It must be noted that as used herein and in the appended claims, thesingular forms “a”, “an”, and “the” include plural referents unless thecontext clearly dictates otherwise. Thus, for example, reference to “ameans” or “the means” includes plurality of such means.

Reference to the term “distal” associated with components of the presentinvention relates to a part of the component situated away from theflexion-extension axis of rotation of the articulating anatomical jointor respectively the joint according to the present invention, andreference to the term “proximal” associated with components of thepresent invention relates to a part of the component situated nearer tothe flexion-extension axis of rotation of the articulating anatomicaljoint or respectively the joint according to the present invention.

Referring now to the drawings, which are provided by way of example andnot limitation, the present invention is directed towards a device fordistraction of an articulating anatomical joint with the function ofeliminating weight and mechanical stress of the physiological load in adamaged anatomical joint for a limited period of time. Whereas thepresent invention is particularly suited to address issues associatedwith osteoarthritis (OA), focal cartilage defects and treatment offractures occurred inside the knee joint, but also the present inventionlends itself to broader applications.

Referring to FIGS. 3 and 4, an external load bearing distracting device1 for an articulating anatomical joint comprising a first component 6configured to be attached to a first anatomical member of thearticulating anatomical joint and a second component 7 operablyassociated with the first component 6; a third component 3 configured tobe attached to a second member of the articulating anatomical joint, anda fourth component 8 operably associated with the third component 3; anda joint 17 joining the second component 7 and the fourth component 8.Said components 6, 7, 3 and 8 are disposed along a longitudinal axis 18in the extension of each other, a segment of the first component 6 isslidably and telescopically arranged inside the second component 7 and asegment the third component 3 is slidably and telescopically arrangedinside the fourth component 8. Said segments are positioned at proximalends of the first component 6 and the third component 3. Each of saidfour components 6, 7, 8 and 3 is preferably carried out of one solidpart. The first component 6 and the third component 3 are rods havinground cross section whose distal ends are configured to be attached tothe first and respectively to the second anatomical member of thearticulating anatomical joint. Distal ends of said first 6 and thirdcomponent 3 are provided with a plurality of perforations 2, throughwhich perforations 2 transcutaneous transverse pins 23 secure the firstcomponent 6 to femur and respectively the third component 3 to tibia tomedial or lateral sides of the anatomical articulating joint.Preferably, the perforations 2 are spaced apart as far as is practicalin order to provide maximum rigidity in the connection between thecomponents 6 and 3 and corresponding bones. The transcutaneous pins 23are formed of metal and are of a type which is well known in the art.Each central part of the first 6 and the third 3 component is providedwith an external threaded portion 24, where on each of the externalthreaded portions 24 is provided a pair of nuts 4 and 5.

The second component 7 and the fourth component 8, within whichcomponents 7 and 8 the first 6 and the third 3 components are arrangedand are capable of sliding along the longitudinal axis 18, are carriedout as hollow bodies, preferably in the form of tubes. In anotherembodiment, the second component 7 and the fourth component 8 may becarried out as guide rails having profile such as C profile or round Cprofile, and the first component 6 and the third component 3 are carriedout as corresponding sliding rails. Depending on the guide railsprofile, first component 6 and the third component 3 may be rods havinground cross section, or may have another cross-section at their proximalend that is slidably arranged inside or along the second component 7 orrespectively the fourth component 8. The second component 7 and thefourth component 8 each comprise a retaining component 15 for limitingaxial longitudinal movement of the first 6 and the third 3 componentsinside the second 7 and respectively the fourth component 8. Eachretaining component 15 is arranged at distal end of the second component7 and of the fourth component 8. The retaining component 15 is carriedout as a widening and is constituent part of the second component 7 andrespectively the fourth component 8, The retaining component 15 has theform of a hollow frame of a rectangular or the like shape, where eachretaining component 15 at its upper (distal) and its lower (proximal)end is provided with orifices through which the first component 6 andthe third component 3 undergo and slide inside or along said second 7and fourth component 8 respectively. Cross-section of said orifices iscorrelated to the cross-sections of the first 6 and the third 3component. In the embodiment where the second component 7 and the fourthcomponent 8 are carried out as guide rails, segments of the first 6 andthe third 3 component at their proximal ends are carried out as railsand their central parts and distal ends are carried out as rods havinground cross section whose distal ends are configured to be attached tothe first and respectively to the second anatomical member of thearticulating anatomical joint. Central parts of the first component 6and of the third component 3 is provided with an external threadedportion. Cross-section of the orifice positioned at the upper end of theretaining component 15 correlates to the cross-section of distal ends ofthe first 6 and the third 3 component, and cross-section of the orificepositioned at the lower end of the retaining component 15 correlates tothe cross-section of the proximal ends of the first 6 and the third 3component carried out as rails.

Said each retaining component 15 is disposed at distal end of the secondcomponent 7 and respectively the fourth component 8, where eachretaining component 15 has dimensions that restricts axial longitudinalmovement of the first component 6 and the third component 3 by thevirtue of the pair of nuts 4 and respectively 5, where each pair of nuts4 and 5 is arranged at the external threaded portion 24 of the firstcomponent 6 and the third component 3, where each threaded portion 24and corresponding pair of nuts 4 and 5 are positioned inside thecorresponding retaining component 15. By means of both respectiveretaining components 15, each pair of nuts 4 and 5 is supported and heldat desired longitudinal position. The retaining component 15 defined bythe rectangular-like shape enables access to each pair of nuts 4 and 5in order to adjust the longitudinal position of the first component 6within the second component 7 and respectively the third component 3within the fourth component 8 thus ensuring that the articulatinganatomical joint is continually distracted. FIG. 5 illustrate thedistracting device 1 installed on the lateral side of a knee joint. Amediolateral axis 19 of rotation of the joint 17 is aligned with theflexion-extension axis of rotation of the articulating anatomical joint.After attaching the first component 6 to femur and the third component 3to tibia, by screwing respective pair of nuts 4 and 5, the first 6 andthe third component 3 are shifted along the longitudinal axis 18 inopposite direction. By shifting the first component 6 and the thirdcomponent 3 away from the mediolateral axis 19 of the joint 17, femurand tibia are mutually distracted to distance corresponding at least toa healthy knee joint.

Referring to FIGS. 3, 4, 6 and 7, according to one embodiment of thepresent invention, a proximal end of the second component 7 forming thejoint 17 is provided with a yoke link 9. Within the yoke link 9 a ballmember 11 is arranged and fixed to yokes 25 of the yoke link 9 by meansof a cross shaft 12. Throughout the yokes 25 of the yoke link 9, theball member 11 and the cross shaft 12 is arranged a bore 13. The bore 13is arranged in the center of rotation of the joint 17. The center ofrotation of the joint 17 is mediolateral axis 19. The bore 13 enablesthe positioning the mediolateral axis 19 of the joint 17, by the virtueof the Kirschner wire, to be aligned with the flexion-extension axis ofthe articulating anatomical joint. The distracting device 1 is anchoredin a position where the mediolateral axis 19 of the joint 17 correspondsto the flexion-extension axis of rotation of the articulating anatomicaljoint, the flexion-extension axis is determined to enableflexion-extension of the articulating anatomical joint for at least 90°.The bore 13 is dimensioned to allow Kirschner wire to pass therethrough.

A proximal end of the fourth component 8 forming the joint 17 is aring-shaped member 10 embracing the ball member 11, whereby the secondcomponent 7 and the fourth component 8 enable rotation and flexing ofthe articulating anatomical joint. Referring to FIGS. 6 and 7, betweenthe ring-shaped member 10 and the ball member 11 is arranged a gap 16.The gap 16 enables additional “slight” medial-lateral translation of thefourth component 8 in respect to the second component 7. Referring toFIG. 4, the fourth component 8 is able to be inclined for an angle α inrespect to the longitudinal axis 18. In addition, the fourth component 8is able to simultaneously revolve around the longitudinal axis 18. Bythis feature the distracting device 1 incorporates freedom oflongitudinal rotation. The value of the angle α is determined by thelength of the yokes 25 of the yoke link 9 and as well by the dimensionof the gap 16. The value of the angle α is preferably such to enableabduction-adduction rotation and simultaneous internal-external rotationof the second member of the anatomical joint in respect of the firstanatomical member of an articulating anatomical joint. In the preferredembodiment of the invention, the value of the angle α is such thatenables said rotations of any knee, irrespective of the individual knee.

According to another embodiment, the joint 17 is carried out by means ofa cardan joint coupled to the fourth component 8 by means of a ballbearing 31. Referring to FIGS. 8 and 9, the joint 17 comprises a yokecylinder having a yoke link 9 arranged at proximal end of the secondcomponent 7. The yoke link 9 is connected to a center block 29 of thecardan joint by virtue of a first pin 26. The first pin 26 undergoingthe center block 29 and the yoke link 9 is positioned at an upper partof the center block 29, the upper part of the center block 29 isarranged inside the yoke link 9. By the means of the first pin 26,abduction-adduction rotation of the fourth component 8 in respect to thesecond component 7 by the angle α is provided (angle α is not shown inthe FIG. 9). At the lower part of the center block 29 is arranged asecond pin 27. The second pin 27 is perpendicular in respect to thefirst pin 26 and connects the center block 29 to a second yoke link 28so that the second yoke link 28 is able to rotate around an axis of thesecond pin 27 whereby providing rotation of the fourth component 8 inrespect to the second component 7, whereby flexion-extension of thesecond member of the anatomical joint in respect of the first anatomicalmember of an articulating anatomical joint is provided. The second yokelink 28 is connected to the ball bearing 31, the ball bearing isarranged at the proximal end of the fourth component 8 in a manner thatthe fourth component 8 rotates around the longitudinal axis 18, wherebyinternal-external rotation of the second member of the anatomical jointin respect of the first anatomical member of an articulating anatomicaljoint is provided. An outer ring of the ball bearing 31 is firmlyconnected to interior round surface of the second yoke link 28, and aninner bore of the ball ring 31 is firmly connected to an outer roundsurface of the fourth component 8. Further, the ball bearing 31 issecured to the proximal end of the forth component 8 by a mean 30. Themean 30 can be nut or by any fixing means well known in the art.Further, the center block 29 is provided with a bore 13, wherein thebore 13 enables the positioning of the joint 17, by the virtue of theKirschner wire, in the flexion-extension axis of rotation of thearticulating anatomical joint enabling its flexion-extension. The bore13 can be arranged to pass through the second pin 27. The bore 13 isdimensioned to allow Kirschner wire to pass therethrough.

In another embodiment of the present invention, the position of theretaining components 15 and of the means 4 and 5 is substituted (notshown in drawings) and described hereafter. The external load bearingdistracting device 1 for an articulating anatomical joint comprising thefirst component 6 configured to be attached to a first anatomical memberof the articulating anatomical joint and the second component 7 operablyassociated with the first component 6; the third component 3 configuredto be attached to the second member of the articulating anatomicaljoint, and the fourth component 8 operably associated with the thirdcomponent 3; and a joint 17 joining the second component 7 and thefourth component 8. Said components 6, 7, 3 and 8 are disposed along alongitudinal axis 18 in the extension of each other. The substitution ofthe position of the retaining components 15 and of the means 4 and 5resulting in that a segment of the second component 7 is slidably andtelescopically arranged inside the first component 6, and a segment thefourth component 8 is slidably and telescopically arranged inside thethird component 3. Said segments are positioned at distal ends of thesecond component 7 and the fourth component 8. Each of said fourcomponents 6, 7, 8 and 3 is preferably carried out of one solid part. Inthis embodiment, each retaining component 15 is arranged at a proximalend of the first component 6 and at proximal end of the third component3. Each central part of the second component 7 and of the fourthcomponent 8 is provided with an external threaded portion 24, where oneach of the external threaded portion 24 is arranged one pair of nuts 4and 5, where each pair of nuts 4 and 5 is positioned inside therespective retaining component 15. By means of both retaining components15 each pair of nuts 4 and 5 is supported and held at desiredlongitudinal position providing distraction of the articulatinganatomical joint. The first 6 and the third 3 component each have ashape of a hollow body, preferably in a form of a tube whose distal endsare provided with a plurality of perforations 2, and the second 7 andthe fourth 8 component are rods having round cross section. Eachretaining component 15 has the shape of a hollow frame of therectangular or a like shape. Further, each retaining component 15 at itsupper and lower end is provided with orifices, through which orificesthe second component 7 undergoes and slides inside the first component6, and the fourth component 8 undergoes and slides inside the thirdcomponent 3. Cross-section of said orifices is correlated to thecross-sections of the second 7 and the fourth 8 component.

In another embodiment, the first component 6 and the third component 3may be carried out as guide rails having profile such as C profile orround C profile, and the second component 7 and the fourth component 8are carried out as corresponding sliding rails. Depending on the guiderails profile, the second component 7 and the fourth component 8 may berods having round cross section or may have another cross-section attheir distal end that is slidably arranged inside or along the firstcomponent 6 or respectively the third component 3.

In the embodiment where the first component 6 and the third component 3are carried out as guide rails, segments of the second 7 and the fourth8 component at their distal ends are carried out as rails and theircentral parts and distal ends are carried out as rods having round crosssection. Distal ends of the first component 6 and the third component 3are configured to be attached to the first and respectively to thesecond anatomical member of the articulating anatomical joint. Centralparts of the second component 7 and of the fourth component 8 areprovided with an external threaded portion. Cross-section of the orificepositioned at the upper end of the retaining component 15 correlates tothe cross-section of distal ends of the second 7 and the fourth 8component carried out as rails, and the cross-section of the orificepositioned at the lower end of the retaining component 15 correlates tothe cross-section of the proximal ends of the second 7 and the fourth 8component.

Components of the distracting device 1 are made from a metal such asstainless steel or titanium alloy, cobalt chromium alloy, or ceramic orare preferably formed from a high strength polymer material such as RCH1000 high molecular weight polyethylene or Hi-Fax 1900 ultra-highmolecular weight polyethylenes to minimize friction and wear.Combinations of materials can also be used to maximize the properties ofmaterials for different components of the present invention. Thetranscutaneous pins 23 are formed of metal and are of a type which iswell known in the art.

Obviously, numerous modifications and variations of the presentinvention are possible in light of the above teachings. It is thereforeto be understood that within the scope of the appended claims, theinvention may be practiced otherwise than as specifically describedherein.

1. An external load bearing distracting device for an articulatinganatomical joint comprising: a first component configured to be attachedto a first anatomical member of the articulating anatomical joint and asecond component operably associated with the first component; a thirdcomponent configured to be attached to a second member of thearticulating anatomical joint and a fourth component operably associatedwith the third component; a joint joining the second component and thefourth component; the joint is being configured to enable natural motionpresent in the articulating anatomical joint; two retaining components;a means enabling adjusting and fixing the first component and the thirdcomponent at desired longitudinal position in relation to a mediolateralaxis of the joint, the mediolateral axis being aligned with theflexion-extension axis of rotation of the articulating anatomical joint,in order to provide distraction of the articulating anatomical joint,wherein: the first component and the second component are slidably andtelescopically interconnected, and the third component and the fourthcomponent are slidably and telescopically interconnected, two componentsof said four components are disposed on opposite sides of themediolateral axis of the joint, and each has a retaining component; andthe other two of said four components each having a locking means forlocking against the retaining components of the two components.
 2. Thedistracting device according to claim 1, wherein the first component andthe second component are slidably and telescopically connected together,and the third component and the fourth component are slidably andtelescopically connected together.
 3. (canceled)
 4. The distractingdevice according to claim 2, wherein the retaining components are at adistal end of the second component and at distal end of the fourthcomponent, and each retaining component has the shape of a hollow frame.5. The distracting device according to claim 2, wherein the retainingcomponents are at a proximal end of the first component and at aproximal end of the third component, and each retaining component hasthe shape of a hollow frame.
 6. The distracting device according toclaim 4, wherein the locking means are two nuts.
 7. The distractingdevice according to claim 6, wherein each central part of the firstcomponent and of the third component is provided with an externalthreaded portion having two threaded nuts provided thereon, where thenuts are positioned inside the retaining component, whereby the firstcomponent is supported and held at desired longitudinal positionrelative to the second component and the third component is supportedand held at desired longitudinal position relative to the fourthcomponent.
 8. The distracting device according to claim 7, wherein thefirst and the third components are: (i) rods having a round crosssection, or (ii) rails, and distal ends of the first and the thirdcomponent are provided with a plurality of perforations.
 9. Thedistracting device according to claim 6, wherein each central part ofthe second component and of the fourth component is provided with anexternal threaded portion, where on each of the external threadedportion is arranged one pair of nuts, where each pair of nuts ispositioned inside the respective retaining component, where by means ofboth retaining components and each pair of nuts the first component andthe third component are supported and held at desired longitudinalposition providing distraction of the articulating anatomical joint. 10.The distracting device according to claim 7, wherein the first and thethird component each have a shape of a hollow body or each is carriedout as guide rail, where distal ends of the first and the thirdcomponent are provided with a plurality of perforations, and the secondand the fourth component are rods having round cross section or thesegments of the second component and the fourth component are carriedout as rails.
 11. The distracting device according to claim 4, whereineach retaining component has orifices at its upper and lower end,whereby a proximal end segment of the first component extends throughorifices in the second component and a proximal end segment of the thirdcomponent extends through orifices in the fourth component.
 12. Thedistracting device according to claim 5, wherein each retainingcomponent at its upper and lower end is provided with orifices, throughwhich orifices the segment of the second component undergoes and slidesinside the first component and the segment of the fourth componentundergoes and slides inside the third component, said segments arepositioned at distal ends of the second component and the fourthcomponent.
 13. The distracting device according to claim 1, wherein thejoint is a ball-and-ring-joint.
 14. The distracting device according toclaim 1, wherein the joint is a cardan joint.
 15. The distracting deviceaccording to claim 13, wherein a proximal end of the second component isprovided with a yoke link, where within the yoke link a ball member isarranged and fixed to a yokes of the yoke link by means of a crossshaft, wherein a bore extends through the yoke link, the ball member andthe cross shaft.
 16. The distracting device according to claim 15,wherein the bore enables the positioning of the joint (17) in theflexion-extension axis of the articulating anatomical joint.
 17. Thedistracting device according to claim 13, wherein a proximal end of thefourth component is a ring-shaped member embracing the ball member, witha gap between the ring-shaped member and the ball member.
 18. Thedistracting device according to claim 14, wherein the cardan jointcomprises a yoke cylinder having a yoke link arranged at proximal end ofthe second component, a second yoke link arranged at proximal end of thefourth component and a center block connected to the yoke link f byvirtue of a first pin and to the second yoke link by virtue of a secondpin, where the first pin and the second pin are mutually perpendicular.19. The distracting device according to claim 18, wherein a bore extendsthrough the center block.
 20. The distracting device according to claim18, wherein a bore extends throughout the second pin.
 21. Thedistracting device according to claim 18, wherein the second yoke linkand the fourth component are mutually coupled by a ball bearing.
 22. Thedistracting device according to claim 21, wherein the ball bearing issecured to the proximal end of the fourth component.
 23. The distractingdevice according to claim 8, further comprising one or more transversepins extending through the perforations in the first and thirdcomponents, for attaching the first component to the first anatomicalmember of the articulating anatomical joint and respectively forattaching the third component to the second anatomical member of thearticulating anatomical joint.
 24. The distracting device according toclaim 23 for use in the treatment of articular cartilage defects inwhich a new articular cartilage formation of a knee joint is required.25. The distracting device according to claim 23 for use in thetreatment of osteoarthritis (OA), focal cartilage defects and treatmentof fractures occurred inside the knee joint.